Make the renderer optional (#17442)

If `VtEngine` gets removed from conhost, we need to be able to run
without any renderer present whatsoever. To make this possible,
I've turned all `Renderer&` into `Renderer*`.

Part of #14000

src/buffer/out/textBuffer.cpp

@@ -48,7 +48,7 @@ TextBuffer::TextBuffer(til::size screenBufferSize,
                        const TextAttribute defaultAttributes,
                        const UINT cursorSize,
                        const bool isActiveBuffer,
-                       Microsoft::Console::Render::Renderer& renderer) :
+                       Microsoft::Console::Render::Renderer* renderer) :
     _renderer{ renderer },
     _currentAttributes{ defaultAttributes },
     // This way every TextBuffer will start with a ""unique"" _lastMutationId
@@ -718,9 +718,9 @@ void TextBuffer::IncrementCircularBuffer(const TextAttribute& fillAttributes)
 {
     // FirstRow is at any given point in time the array index in the circular buffer that corresponds
     // to the logical position 0 in the window (cursor coordinates and all other coordinates).
-    if (_isActiveBuffer)
+    if (_isActiveBuffer && _renderer)
     {
-        _renderer.TriggerFlush(true);
+        _renderer->TriggerFlush(true);
     }
 
     // Prune hyperlinks to delete obsolete references
@@ -1063,56 +1063,56 @@ bool TextBuffer::IsActiveBuffer() const noexcept
     return _isActiveBuffer;
 }
 
-Microsoft::Console::Render::Renderer& TextBuffer::GetRenderer() noexcept
+Microsoft::Console::Render::Renderer* TextBuffer::GetRenderer() noexcept
 {
     return _renderer;
 }
 
 void TextBuffer::NotifyPaintFrame() noexcept
 {
-    if (_isActiveBuffer)
+    if (_isActiveBuffer && _renderer)
     {
-        _renderer.NotifyPaintFrame();
+        _renderer->NotifyPaintFrame();
     }
 }
 
 void TextBuffer::TriggerRedraw(const Viewport& viewport)
 {
-    if (_isActiveBuffer)
+    if (_isActiveBuffer && _renderer)
     {
-        _renderer.TriggerRedraw(viewport);
+        _renderer->TriggerRedraw(viewport);
     }
 }
 
 void TextBuffer::TriggerRedrawAll()
 {
-    if (_isActiveBuffer)
+    if (_isActiveBuffer && _renderer)
     {
-        _renderer.TriggerRedrawAll();
+        _renderer->TriggerRedrawAll();
     }
 }
 
 void TextBuffer::TriggerScroll()
 {
-    if (_isActiveBuffer)
+    if (_isActiveBuffer && _renderer)
     {
-        _renderer.TriggerScroll();
+        _renderer->TriggerScroll();
     }
 }
 
 void TextBuffer::TriggerScroll(const til::point delta)
 {
-    if (_isActiveBuffer)
+    if (_isActiveBuffer && _renderer)
     {
-        _renderer.TriggerScroll(&delta);
+        _renderer->TriggerScroll(&delta);
     }
 }
 
 void TextBuffer::TriggerNewTextNotification(const std::wstring_view newText)
 {
-    if (_isActiveBuffer)
+    if (_isActiveBuffer && _renderer)
     {
-        _renderer.TriggerNewTextNotification(newText);
+        _renderer->TriggerNewTextNotification(newText);
     }
 }
 

src/buffer/out/textBuffer.hpp

@@ -72,7 +72,7 @@ public:
                const TextAttribute defaultAttributes,
                const UINT cursorSize,
                const bool isActiveBuffer,
-               Microsoft::Console::Render::Renderer& renderer);
+               Microsoft::Console::Render::Renderer* renderer);
 
     TextBuffer(const TextBuffer&) = delete;
     TextBuffer(TextBuffer&&) = delete;
@@ -161,7 +161,7 @@ public:
     void SetAsActiveBuffer(const bool isActiveBuffer) noexcept;
     bool IsActiveBuffer() const noexcept;
 
-    Microsoft::Console::Render::Renderer& GetRenderer() noexcept;
+    Microsoft::Console::Render::Renderer* GetRenderer() noexcept;
 
     void NotifyPaintFrame() noexcept;
     void TriggerRedraw(const Microsoft::Console::Types::Viewport& viewport);
@@ -333,7 +333,7 @@ private:
 
     static void _AppendRTFText(std::string& contentBuilder, const std::wstring_view& text);
 
-    Microsoft::Console::Render::Renderer& _renderer;
+    Microsoft::Console::Render::Renderer* _renderer = nullptr;
 
     std::unordered_map<uint16_t, std::wstring> _hyperlinkMap;
     std::unordered_map<std::wstring, uint16_t> _hyperlinkCustomIdMap;

src/buffer/out/ut_textbuffer/ReflowTests.cpp

@@ -699,7 +699,7 @@ class ReflowTests
     static DummyRenderer renderer;
     static std::unique_ptr<TextBuffer> _textBufferFromTestBuffer(const TestBuffer& testBuffer)
     {
-        auto buffer = std::make_unique<TextBuffer>(testBuffer.size, TextAttribute{ 0x7 }, 0, false, renderer);
+        auto buffer = std::make_unique<TextBuffer>(testBuffer.size, TextAttribute{ 0x7 }, 0, false, &renderer);
 
         til::CoordType y = 0;
         for (const auto& testRow : testBuffer.rows)
@@ -725,7 +725,7 @@ class ReflowTests
 
     static std::unique_ptr<TextBuffer> _textBufferByReflowingTextBuffer(TextBuffer& originalBuffer, const til::size newSize)
     {
-        auto buffer = std::make_unique<TextBuffer>(newSize, TextAttribute{ 0x7 }, 0, false, renderer);
+        auto buffer = std::make_unique<TextBuffer>(newSize, TextAttribute{ 0x7 }, 0, false, &renderer);
         TextBuffer::Reflow(originalBuffer, *buffer);
         return buffer;
     }

src/buffer/out/ut_textbuffer/UTextAdapterTests.cpp

@@ -37,7 +37,7 @@ class UTextAdapterTests
     TEST_METHOD(Unicode)
     {
         DummyRenderer renderer;
-        TextBuffer buffer{ til::size{ 24, 1 }, TextAttribute{}, 0, false, renderer };
+        TextBuffer buffer{ til::size{ 24, 1 }, TextAttribute{}, 0, false, &renderer };
 
         RowWriteState state{
             .text = L"abc 𝒶𝒷𝒸 abc ネコちゃん",

src/cascadia/TerminalControl/ControlCore.cpp

@@ -1894,7 +1894,7 @@ namespace winrt::Microsoft::Terminal::Control::implementation
         const auto lock = _terminal->LockForWriting();
 
         auto& renderSettings = _terminal->GetRenderSettings();
-        renderSettings.ToggleBlinkRendition(*_renderer);
+        renderSettings.ToggleBlinkRendition(_renderer.get());
     }
 
     void ControlCore::BlinkCursor()

src/cascadia/TerminalCore/Terminal.cpp

@@ -47,9 +47,9 @@ void Terminal::Create(til::size viewportSize, til::CoordType scrollbackLines, Re
                                 Utils::ClampToShortMax(viewportSize.height + scrollbackLines, 1) };
     const TextAttribute attr{};
     const UINT cursorSize = 12;
-    _mainBuffer = std::make_unique<TextBuffer>(bufferSize, attr, cursorSize, true, renderer);
+    _mainBuffer = std::make_unique<TextBuffer>(bufferSize, attr, cursorSize, true, &renderer);
 
-    auto dispatch = std::make_unique<AdaptDispatch>(*this, renderer, _renderSettings, _terminalInput);
+    auto dispatch = std::make_unique<AdaptDispatch>(*this, &renderer, _renderSettings, _terminalInput);
     auto engine = std::make_unique<OutputStateMachineEngine>(std::move(dispatch));
     _stateMachine = std::make_unique<StateMachine>(std::move(engine));
 

src/host/screenInfo.cpp

@@ -117,7 +117,7 @@ SCREEN_INFORMATION::~SCREEN_INFORMATION()
                                                             defaultAttributes,
                                                             uiCursorSize,
                                                             pScreen->IsActiveScreenBuffer(),
-                                                            *ServiceLocator::LocateGlobals().pRender);
+                                                            ServiceLocator::LocateGlobals().pRender);
 
         const auto& gci = ServiceLocator::LocateGlobals().getConsoleInformation();
         pScreen->_textBuffer->GetCursor().SetType(gci.GetCursorType());
@@ -253,10 +253,9 @@ void SCREEN_INFORMATION::s_RemoveScreenBuffer(_In_ SCREEN_INFORMATION* const pSc
     {
         auto& g = ServiceLocator::LocateGlobals();
         auto& gci = g.getConsoleInformation();
-        auto& renderer = *g.pRender;
         auto& renderSettings = gci.GetRenderSettings();
         auto& terminalInput = gci.GetActiveInputBuffer()->GetTerminalInput();
-        auto adapter = std::make_unique<AdaptDispatch>(_api, renderer, renderSettings, terminalInput);
+        auto adapter = std::make_unique<AdaptDispatch>(_api, g.pRender, renderSettings, terminalInput);
         auto engine = std::make_unique<OutputStateMachineEngine>(std::move(adapter));
         // Note that at this point in the setup, we haven't determined if we're
         //      in VtIo mode or not yet. We'll set the OutputStateMachine's

src/host/ut_host/TextBufferTests.cpp

@@ -1542,7 +1542,7 @@ void TextBufferTests::ResizeTraditional()
     const til::size smallSize = { 5, 5 };
     const TextAttribute defaultAttr(0);
 
-    TextBuffer buffer(smallSize, defaultAttr, 12, false, _renderer);
+    TextBuffer buffer(smallSize, defaultAttr, 12, false, &_renderer);
 
     Log::Comment(L"Fill buffer with some data and do assorted resize operations.");
 
@@ -1638,7 +1638,7 @@ void TextBufferTests::ResizeTraditionalRotationPreservesHighUnicode()
     const til::size bufferSize{ 80, 10 };
     const UINT cursorSize = 12;
     const TextAttribute attr{ 0x7f };
-    auto _buffer = std::make_unique<TextBuffer>(bufferSize, attr, cursorSize, false, _renderer);
+    auto _buffer = std::make_unique<TextBuffer>(bufferSize, attr, cursorSize, false, &_renderer);
 
     // Get a position inside the buffer
     const til::point pos{ 2, 1 };
@@ -1679,7 +1679,7 @@ void TextBufferTests::ScrollBufferRotationPreservesHighUnicode()
     const til::size bufferSize{ 80, 10 };
     const UINT cursorSize = 12;
     const TextAttribute attr{ 0x7f };
-    auto _buffer = std::make_unique<TextBuffer>(bufferSize, attr, cursorSize, false, _renderer);
+    auto _buffer = std::make_unique<TextBuffer>(bufferSize, attr, cursorSize, false, &_renderer);
 
     // Get a position inside the buffer
     const til::point pos{ 2, 1 };
@@ -1714,7 +1714,7 @@ void TextBufferTests::ResizeTraditionalHighUnicodeRowRemoval()
     const til::size bufferSize{ 80, 10 };
     const UINT cursorSize = 12;
     const TextAttribute attr{ 0x7f };
-    auto _buffer = std::make_unique<TextBuffer>(bufferSize, attr, cursorSize, false, _renderer);
+    auto _buffer = std::make_unique<TextBuffer>(bufferSize, attr, cursorSize, false, &_renderer);
 
     // Get a position inside the buffer in the bottom row
     const til::point pos{ 0, bufferSize.height - 1 };
@@ -1744,7 +1744,7 @@ void TextBufferTests::ResizeTraditionalHighUnicodeColumnRemoval()
     const til::size bufferSize{ 80, 10 };
     const UINT cursorSize = 12;
     const TextAttribute attr{ 0x7f };
-    auto _buffer = std::make_unique<TextBuffer>(bufferSize, attr, cursorSize, false, _renderer);
+    auto _buffer = std::make_unique<TextBuffer>(bufferSize, attr, cursorSize, false, &_renderer);
 
     // Get a position inside the buffer in the last column (-2 as the inserted character is 2 columns wide).
     const til::point pos{ bufferSize.width - 2, 0 };
@@ -1771,7 +1771,7 @@ void TextBufferTests::TestOverwriteChars()
     til::size bufferSize{ 10, 3 };
     UINT cursorSize = 12;
     TextAttribute attr{ 0x7f };
-    TextBuffer buffer{ bufferSize, attr, cursorSize, false, _renderer };
+    TextBuffer buffer{ bufferSize, attr, cursorSize, false, &_renderer };
     auto& row = buffer.GetMutableRowByOffset(0);
 
 // scientist emoji U+1F9D1 U+200D U+1F52C
@@ -1827,7 +1827,7 @@ void TextBufferTests::TestReplace()
     static constexpr til::size bufferSize{ 10, 3 };
     static constexpr UINT cursorSize = 12;
     const TextAttribute attr{ 0x7f };
-    TextBuffer buffer{ bufferSize, attr, cursorSize, false, _renderer };
+    TextBuffer buffer{ bufferSize, attr, cursorSize, false, &_renderer };
 
 #define complex L"\U0001F41B"
 
@@ -1909,7 +1909,7 @@ void TextBufferTests::TestInsert()
     static constexpr TextAttribute attr1{ 0x11111111, 0x00000000 };
     static constexpr TextAttribute attr2{ 0x22222222, 0x00000000 };
     static constexpr TextAttribute attr3{ 0x33333333, 0x00000000 };
-    TextBuffer buffer{ bufferSize, attr1, cursorSize, false, _renderer };
+    TextBuffer buffer{ bufferSize, attr1, cursorSize, false, &_renderer };
 
     struct Test
     {
@@ -2048,7 +2048,7 @@ void TextBufferTests::GetWordBoundaries()
     til::size bufferSize{ 80, 9001 };
     UINT cursorSize = 12;
     TextAttribute attr{ 0x7f };
-    auto _buffer = std::make_unique<TextBuffer>(bufferSize, attr, cursorSize, false, _renderer);
+    auto _buffer = std::make_unique<TextBuffer>(bufferSize, attr, cursorSize, false, &_renderer);
 
     // Setup: Write lines of text to the buffer
     const std::vector<std::wstring> text = { L"word other",
@@ -2264,7 +2264,7 @@ void TextBufferTests::MoveByWord()
     til::size bufferSize{ 80, 9001 };
     UINT cursorSize = 12;
     TextAttribute attr{ 0x7f };
-    auto _buffer = std::make_unique<TextBuffer>(bufferSize, attr, cursorSize, false, _renderer);
+    auto _buffer = std::make_unique<TextBuffer>(bufferSize, attr, cursorSize, false, &_renderer);
 
     // Setup: Write lines of text to the buffer
     const std::vector<std::wstring> text = { L"word other",
@@ -2371,7 +2371,7 @@ void TextBufferTests::GetGlyphBoundaries()
     til::size bufferSize{ 10, 10 };
     UINT cursorSize = 12;
     TextAttribute attr{ 0x7f };
-    auto _buffer = std::make_unique<TextBuffer>(bufferSize, attr, cursorSize, false, _renderer);
+    auto _buffer = std::make_unique<TextBuffer>(bufferSize, attr, cursorSize, false, &_renderer);
 
     // This is the burrito emoji: 🌯
     // It's encoded in UTF-16, as needed by the buffer.
@@ -2407,7 +2407,7 @@ void TextBufferTests::GetTextRects()
     til::size bufferSize{ 20, 50 };
     UINT cursorSize = 12;
     TextAttribute attr{ 0x7f };
-    auto _buffer = std::make_unique<TextBuffer>(bufferSize, attr, cursorSize, false, _renderer);
+    auto _buffer = std::make_unique<TextBuffer>(bufferSize, attr, cursorSize, false, &_renderer);
 
     // Setup: Write lines of text to the buffer
     const std::vector<std::wstring> text = { L"0123456789",
@@ -2487,7 +2487,7 @@ void TextBufferTests::GetPlainText()
         til::size bufferSize{ 10, 20 };
         UINT cursorSize = 12;
         TextAttribute attr{ 0x7f };
-        auto _buffer = std::make_unique<TextBuffer>(bufferSize, attr, cursorSize, false, _renderer);
+        auto _buffer = std::make_unique<TextBuffer>(bufferSize, attr, cursorSize, false, &_renderer);
 
         // Setup: Write lines of text to the buffer
         const std::vector<std::wstring> bufferText = { L"12345",
@@ -2575,7 +2575,7 @@ void TextBufferTests::GetPlainText()
         til::size bufferSize{ 5, 20 };
         UINT cursorSize = 12;
         TextAttribute attr{ 0x7f };
-        auto _buffer = std::make_unique<TextBuffer>(bufferSize, attr, cursorSize, false, _renderer);
+        auto _buffer = std::make_unique<TextBuffer>(bufferSize, attr, cursorSize, false, &_renderer);
 
         // Setup: Write lines of text to the buffer
         const std::vector<std::wstring> bufferText = { L"1234567",
@@ -2704,7 +2704,7 @@ void TextBufferTests::HyperlinkTrim()
     const til::size bufferSize{ 80, 10 };
     const UINT cursorSize = 12;
     const TextAttribute attr{ 0x7f };
-    auto _buffer = std::make_unique<TextBuffer>(bufferSize, attr, cursorSize, false, _renderer);
+    auto _buffer = std::make_unique<TextBuffer>(bufferSize, attr, cursorSize, false, &_renderer);
 
     static constexpr std::wstring_view url{ L"test.url" };
     static constexpr std::wstring_view otherUrl{ L"other.url" };
@@ -2750,7 +2750,7 @@ void TextBufferTests::NoHyperlinkTrim()
     const til::size bufferSize{ 80, 10 };
     const UINT cursorSize = 12;
     const TextAttribute attr{ 0x7f };
-    auto _buffer = std::make_unique<TextBuffer>(bufferSize, attr, cursorSize, false, _renderer);
+    auto _buffer = std::make_unique<TextBuffer>(bufferSize, attr, cursorSize, false, &_renderer);
 
     static constexpr std::wstring_view url{ L"test.url" };
     static constexpr std::wstring_view customId{ L"CustomId" };
@@ -2902,7 +2902,7 @@ void TextBufferTests::ReflowPromptRegions()
 
     // After we resize, make sure to get the new textBuffers
     til::size newSize{ oldSize.Width() + dx, oldSize.Height() };
-    auto newBuffer = std::make_unique<TextBuffer>(newSize, TextAttribute{ 0x7 }, 0, false, _renderer);
+    auto newBuffer = std::make_unique<TextBuffer>(newSize, TextAttribute{ 0x7 }, 0, false, &_renderer);
     TextBuffer::Reflow(*tbi, *newBuffer);
 
     Log::Comment(L"========== Checking the host buffer state (after) ==========");

src/inc/test/CommonState.hpp

@@ -188,7 +188,7 @@ public:
                                                                                   initialAttributes,
                                                                                   uiCursorSize,
                                                                                   true,
-                                                                                  *g.pRender);
+                                                                                  g.pRender);
             if (textBuffer.get() == nullptr)
             {
                 m_hrTextBufferInfo = E_OUTOFMEMORY;

src/renderer/base/RenderSettings.cpp

@@ -259,7 +259,7 @@ COLORREF RenderSettings::GetAttributeUnderlineColor(const TextAttribute& attr) c
 //   renderer if there are blinking cells currently in view.
 // Arguments:
 // - renderer: the renderer that will be redrawn.
-void RenderSettings::ToggleBlinkRendition(Renderer& renderer) noexcept
+void RenderSettings::ToggleBlinkRendition(Renderer* renderer) noexcept
 try
 {
     if (GetRenderMode(Mode::BlinkAllowed))
@@ -277,7 +277,10 @@ try
             // We reset the _blinkIsInUse flag before redrawing, so we can
             // get a fresh assessment of the current blink attribute usage.
             _blinkIsInUse = false;
-            renderer.TriggerRedrawAll();
+            if (renderer)
+            {
+                renderer->TriggerRedrawAll();
+            }
         }
     }
 }

src/renderer/inc/RenderSettings.hpp

@@ -42,7 +42,7 @@ namespace Microsoft::Console::Render
         std::pair<COLORREF, COLORREF> GetAttributeColors(const TextAttribute& attr) const noexcept;
         std::pair<COLORREF, COLORREF> GetAttributeColorsWithAlpha(const TextAttribute& attr) const noexcept;
         COLORREF GetAttributeUnderlineColor(const TextAttribute& attr) const noexcept;
-        void ToggleBlinkRendition(class Renderer& renderer) noexcept;
+        void ToggleBlinkRendition(class Renderer* renderer) noexcept;
 
     private:
         til::enumset<Mode> _renderMode{ Mode::BlinkAllowed, Mode::IntenseIsBright };

src/terminal/adapter/PageManager.cpp

@@ -99,7 +99,7 @@ void Page::MoveViewportDown() noexcept
     _viewport.bottom++;
 }
 
-PageManager::PageManager(ITerminalApi& api, Renderer& renderer) noexcept :
+PageManager::PageManager(ITerminalApi& api, Renderer* renderer) noexcept :
     _api{ api },
     _renderer{ renderer }
 {
@@ -220,9 +220,9 @@ void PageManager::MoveTo(const til::CoordType pageNumber, const bool makeVisible
     }
 
     _activePageNumber = newPageNumber;
-    if (redrawRequired)
+    if (redrawRequired && _renderer)
     {
-        _renderer.TriggerRedrawAll();
+        _renderer->TriggerRedrawAll();
     }
 }
 

src/terminal/adapter/PageManager.hpp

@@ -46,7 +46,7 @@ namespace Microsoft::Console::VirtualTerminal
         using Renderer = Microsoft::Console::Render::Renderer;
 
     public:
-        PageManager(ITerminalApi& api, Renderer& renderer) noexcept;
+        PageManager(ITerminalApi& api, Renderer* renderer) noexcept;
         void Reset();
         Page Get(const til::CoordType pageNumber) const;
         Page ActivePage() const;
@@ -59,7 +59,7 @@ namespace Microsoft::Console::VirtualTerminal
         TextBuffer& _getBuffer(const til::CoordType pageNumber, const til::size pageSize) const;
 
         ITerminalApi& _api;
-        Renderer& _renderer;
+        Renderer* _renderer;
         til::CoordType _activePageNumber = 1;
         til::CoordType _visiblePageNumber = 1;
         static constexpr til::CoordType MAX_PAGES = 6;

src/terminal/adapter/adaptDispatch.cpp

@@ -16,7 +16,7 @@ using namespace Microsoft::Console::VirtualTerminal;
 
 static constexpr std::wstring_view whitespace{ L" " };
 
-AdaptDispatch::AdaptDispatch(ITerminalApi& api, Renderer& renderer, RenderSettings& renderSettings, TerminalInput& terminalInput) noexcept :
+AdaptDispatch::AdaptDispatch(ITerminalApi& api, Renderer* renderer, RenderSettings& renderSettings, TerminalInput& terminalInput) noexcept :
     _api{ api },
     _renderer{ renderer },
     _renderSettings{ renderSettings },
@@ -1937,7 +1937,10 @@ bool AdaptDispatch::_ModeParamsHelper(const DispatchTypes::ModeParams param, con
         {
             return false;
         }
-        _renderer.TriggerRedrawAll();
+        if (_renderer)
+        {
+            _renderer->TriggerRedrawAll();
+        }
         return true;
     case DispatchTypes::ModeParams::DECOM_OriginMode:
         _modes.set(Mode::Origin, enable);
@@ -3221,7 +3224,10 @@ bool AdaptDispatch::HardReset()
     TabSet(DispatchTypes::TabSetType::SetEvery8Columns);
 
     // Clear the soft font in the renderer and delete the font buffer.
-    _renderer.UpdateSoftFont({}, {}, false);
+    if (_renderer)
+    {
+        _renderer->UpdateSoftFont({}, {}, false);
+    }
     _fontBuffer = nullptr;
 
     // Reset internal modes to their initial state
@@ -3501,18 +3507,20 @@ bool AdaptDispatch::SetColorTableEntry(const size_t tableIndex, const DWORD dwCo
         return false;
     }
 
-    // If we're updating the background color, we need to let the renderer
+    if (_renderer)
-    // know, since it may want to repaint the window background to match.
+    {
-    const auto backgroundIndex = _renderSettings.GetColorAliasIndex(ColorAlias::DefaultBackground);
+        // If we're updating the background color, we need to let the renderer
-    const auto backgroundChanged = (tableIndex == backgroundIndex);
+        // know, since it may want to repaint the window background to match.
+        const auto backgroundIndex = _renderSettings.GetColorAliasIndex(ColorAlias::DefaultBackground);
+        const auto backgroundChanged = (tableIndex == backgroundIndex);
 
-    // Similarly for the frame color, the tab may need to be repainted.
+        // Similarly for the frame color, the tab may need to be repainted.
-    const auto frameIndex = _renderSettings.GetColorAliasIndex(ColorAlias::FrameBackground);
+        const auto frameIndex = _renderSettings.GetColorAliasIndex(ColorAlias::FrameBackground);
-    const auto frameChanged = (tableIndex == frameIndex);
+        const auto frameChanged = (tableIndex == frameIndex);
+
+        _renderer->TriggerRedrawAll(backgroundChanged, frameChanged);
+    }
 
-    // Update the screen colors if we're not a pty
-    // No need to force a redraw in pty mode.
-    _renderer.TriggerRedrawAll(backgroundChanged, frameChanged);
     return true;
 }
 
@@ -3566,14 +3574,19 @@ bool AdaptDispatch::AssignColor(const DispatchTypes::ColorItem item, const VTInt
     }
 
     // No need to force a redraw in pty mode.
-    const auto inPtyMode = _api.IsConsolePty();
+    if (_api.IsConsolePty())
-    if (!inPtyMode)
+    {
+        return false;
+    }
+
+    if (_renderer)
     {
         const auto backgroundChanged = item == DispatchTypes::ColorItem::NormalText;
         const auto frameChanged = item == DispatchTypes::ColorItem::WindowFrame;
-        _renderer.TriggerRedrawAll(backgroundChanged, frameChanged);
+        _renderer->TriggerRedrawAll(backgroundChanged, frameChanged);
     }
-    return !inPtyMode;
+
+    return true;
 }
 
 //Routine Description:
@@ -3769,11 +3782,11 @@ bool AdaptDispatch::DoConEmuAction(const std::wstring_view string)
 bool AdaptDispatch::DoITerm2Action(const std::wstring_view string)
 {
     const auto isConPty = _api.IsConsolePty();
-    if (isConPty)
+    if (isConPty && _renderer)
     {
         // Flush the frame manually, to make sure marks end up on the right
         // line, like the alt buffer sequence.
-        _renderer.TriggerFlush(false);
+        _renderer->TriggerFlush(false);
     }
 
     if constexpr (!Feature_ScrollbarMarks::IsEnabled())
@@ -3813,11 +3826,11 @@ bool AdaptDispatch::DoITerm2Action(const std::wstring_view string)
 bool AdaptDispatch::DoFinalTermAction(const std::wstring_view string)
 {
     const auto isConPty = _api.IsConsolePty();
-    if (isConPty)
+    if (isConPty && _renderer)
     {
         // Flush the frame manually, to make sure marks end up on the right
         // line, like the alt buffer sequence.
-        _renderer.TriggerFlush(false);
+        _renderer->TriggerFlush(false);
     }
 
     if constexpr (!Feature_ScrollbarMarks::IsEnabled())
@@ -3904,10 +3917,10 @@ bool AdaptDispatch::DoFinalTermAction(const std::wstring_view string)
 bool AdaptDispatch::DoVsCodeAction(const std::wstring_view string)
 {
     // This is not implemented in conhost.
-    if (_api.IsConsolePty())
+    if (_api.IsConsolePty() && _renderer)
     {
         // Flush the frame manually to make sure this action happens at the right time.
-        _renderer.TriggerFlush(false);
+        _renderer->TriggerFlush(false);
         return false;
     }
 
@@ -4048,10 +4061,13 @@ ITermDispatch::StringHandler AdaptDispatch::DownloadDRCS(const VTInt fontNumber,
             {
                 _termOutput.SetDrcs94Designation(_fontBuffer->GetDesignation());
             }
-            const auto bitPattern = _fontBuffer->GetBitPattern();
+            if (_renderer)
-            const auto cellSize = _fontBuffer->GetCellSize();
+            {
-            const auto centeringHint = _fontBuffer->GetTextCenteringHint();
+                const auto bitPattern = _fontBuffer->GetBitPattern();
-            _renderer.UpdateSoftFont(bitPattern, cellSize, centeringHint);
+                const auto cellSize = _fontBuffer->GetCellSize();
+                const auto centeringHint = _fontBuffer->GetTextCenteringHint();
+                _renderer->UpdateSoftFont(bitPattern, cellSize, centeringHint);
+            }
         }
         return true;
     };
@@ -4912,9 +4928,9 @@ bool AdaptDispatch::PlaySounds(const VTParameters parameters)
     // If we're a conpty, we return false so the command will be passed on
     // to the connected terminal. But we need to flush the current frame
     // first, otherwise the visual output will lag behind the sound.
-    if (_api.IsConsolePty())
+    if (_api.IsConsolePty() && _renderer)
     {
-        _renderer.TriggerFlush(false);
+        _renderer->TriggerFlush(false);
         return false;
     }
 
@@ -4948,7 +4964,11 @@ ITermDispatch::StringHandler AdaptDispatch::_CreatePassthroughHandler()
 {
     // Before we pass through any more data, we need to flush the current frame
     // first, otherwise it can end up arriving out of sync.
-    _renderer.TriggerFlush(false);
+    if (_renderer)
+    {
+        _renderer->TriggerFlush(false);
+    }
+
     // Then we need to flush the sequence introducer and parameters that have
     // already been parsed by the state machine.
     auto& stateMachine = _api.GetStateMachine();

src/terminal/adapter/adaptDispatch.hpp

@@ -36,7 +36,7 @@ namespace Microsoft::Console::VirtualTerminal
         using RenderSettings = Microsoft::Console::Render::RenderSettings;
 
     public:
-        AdaptDispatch(ITerminalApi& api, Renderer& renderer, RenderSettings& renderSettings, TerminalInput& terminalInput) noexcept;
+        AdaptDispatch(ITerminalApi& api, Renderer* renderer, RenderSettings& renderSettings, TerminalInput& terminalInput) noexcept;
 
         void Print(const wchar_t wchPrintable) override;
         void PrintString(const std::wstring_view string) override;
@@ -286,7 +286,7 @@ namespace Microsoft::Console::VirtualTerminal
         bool _initDefaultTabStops = true;
 
         ITerminalApi& _api;
-        Renderer& _renderer;
+        Renderer* _renderer;
         RenderSettings& _renderSettings;
         TerminalInput& _terminalInput;
         TerminalOutput _termOutput;

src/terminal/adapter/ut_adapter/adapterTest.cpp

@@ -250,7 +250,7 @@ public:
         _setTextAttributesResult = TRUE;
         _returnResponseResult = TRUE;
 
-        _textBuffer = std::make_unique<TextBuffer>(til::size{ 100, 600 }, TextAttribute{}, 0, false, _renderer);
+        _textBuffer = std::make_unique<TextBuffer>(til::size{ 100, 600 }, TextAttribute{}, 0, false, &_renderer);
 
         // Viewport sitting in the "middle" of the buffer somewhere (so all sides have excess buffer around them)
         _viewport.top = 20;
@@ -406,7 +406,7 @@ public:
             _terminalInput = TerminalInput{};
             auto& renderer = _testGetSet->_renderer;
             auto& renderSettings = renderer._renderSettings;
-            auto adapter = std::make_unique<AdaptDispatch>(*_testGetSet, renderer, renderSettings, _terminalInput);
+            auto adapter = std::make_unique<AdaptDispatch>(*_testGetSet, &renderer, renderSettings, _terminalInput);
 
             fSuccess = adapter.get() != nullptr;
             if (fSuccess)
@@ -2448,7 +2448,7 @@ public:
         Log::Comment(L"Starting test...");
 
         til::inclusive_rect srTestMargins;
-        _testGetSet->_textBuffer = std::make_unique<TextBuffer>(til::size{ 100, 600 }, TextAttribute{}, 0, false, _testGetSet->_renderer);
+        _testGetSet->_textBuffer = std::make_unique<TextBuffer>(til::size{ 100, 600 }, TextAttribute{}, 0, false, &_testGetSet->_renderer);
         _testGetSet->_viewport.right = 8;
         _testGetSet->_viewport.bottom = 8;
         auto sScreenHeight = _testGetSet->_viewport.bottom - _testGetSet->_viewport.top;